Field of the Invention
The present invention relates to a projection image display that projects an image from the back and displays the image.
Description of the Background Art
Rear projection image displays have been known as projection image displays that project images onto a back surface of a screen from a projection unit. In a typical rear projection image display, a screen unit including a screen is removably attached, with screws, to a front surface of a housing from a back surface of the housing in which a projection unit is housed.
In recent years, space savings in installation of a projection image display allow a back surface of a housing to be closely installed on a wall, and the projection image display that allows all maintenance from a front surface of the housing has been developed. Thus, a simplification of the structures and a cost reduction are needed. For display on a large screen, a plurality of projection image displays are typically combined to be used.
The projection image display that allows maintenance from the front surface of the housing includes a projection image display capable of finely adjusting installation of a screen unit (for example, see Japanese Patent No. 5279456).
A device disclosed in Japanese Patent No. 5279456 includes a mechanism that is located inside the device and finely adjusts the position of the screen unit. A screen needs to be opened for the adjustment from the inside, which does not allow the adjustment while the screen unit is closely attached to a housing. To solve this problem, Japanese Patent No. 5279456 discloses a method of temporarily combining the adjustment mechanism with a driving mechanism that can be remotely controlled. However, after the adjustment, the screen unit needs to be opened and closed once, and the driving mechanism that can be remotely controlled needs to be taken out, so that the screen unit moves out of adjustment and needs predictive adjustments due to a need for the opening and closing.
In Japanese Patent No. 5279456, a hook projection formed as a locking means in a slide mechanism fits in a groove that can be fit with the hook projection and is formed in the screen unit, to thereby lock the screen unit. A likelihood of approximately 1 mm is provided to securely fit them together, but this likelihood results in looseness of the screen unit.